Exemplary embodiments pertain to the art of electric machines and, more particularly to an alternator having a heat sink.
Most motor vehicles include an alternator that transforms mechanical energy into electrical energy that is used to charge an on-board battery. Generally, alternators fall into two categories: brushed alternators, and brushless alternators. Brushed alternators include a rotor having rotor windings that is rotated within a stator. The rotor includes a pair of slip rings that are electrically coupled to the rotor windings, that when energized create rotating magnetic fields. The slip rings are in sliding contact with stationary brushes. With this arrangement, rotation of the rotor relative to the stator passes magnetic fields through the stator winding creating a current in the stator. The current is conditioned and employed to charge a battery or support vehicle electrical loads.
Brushless alternators work in the same way as brush type alternators except that there are no brushes to carry current. Brushless alternators include a main alternator and an exciter having a stationary field winding. In the exciter, the field winding creates magnetic fields in the rotor as the rotor rotates in close proximity to a large core mounted on the rotor shaft. The main alternator includes a rotor and a stationary armature or stator. Varying current through the exciter field coil varies output from the stator. The output is rectified by a stationary rectifier assembly mounted to the machine thereby creating a DC current. A portion of the DC current is passed back to the field winding to establish an alternator output. The alternator output is then employed to charge a vehicle battery or support vehicle electrical loads. Regardless of which system is employed, vehicle alternators include heat sinks that are arranged to remove heat by conduction or convection from various alternator electronic components.